Digital Elevation Models as a Tool for Monitoring and Evaluating Gully Development in a Humid Tropical Environment

Gully erosion is a serious geo-environmental issue causing land degradation in different parts of South Eastern Nigeria. In this study, DEMs were generated at different spatial scales viz; Order-3 Basin, Order-1 and Dominic Utuk Avenue gully sub-catchment in Uyo area of Akwa Ibom State, South Eastern Nigeria. The study was conducted to achieve the following objectives viz; generate the geospatial database applying the principles of Geographic Information System (GIS) and field measurements, conduct catchment analysis; specifically erosion estimation studies, employ GIS in mapping the entire catchment area vis-a-vis erosion prone areas and compute the maximum discharge in the sub-catchment area to aid in the design of erosion control structures. The results obtained, i.e., 78.9 m3 sec-1 pre-supposes that a rainfall event that lasts for an hour will generate a maximum discharge of 111.127 m3 sec-1 into the gully complex; while, a rainstorms of 3 h duration will generate a maximum discharge of 333.38 m3 sec-1 into the gully system. The results of the research has implications for gully erosion stabilization/control in the study area.